The present invention relates to a plating apparatus for plating a substrate such as a semiconductor wafer or the like, and particularly to a plating apparatus capable of forming a plating film of uniform thickness by uniformly conducting a current on the substrate.
FIG. 1 shows the general construction of this type of conventional plating apparatus. As shown in the drawing, the plating apparatus includes a plating bath 10 accommodating a plating solution Q, in which a substrate 12 such as a semiconductor wafer or the like mounted on a jig 11 and an anode 13 are disposed oppositely. A power source 14 applies a predetermined DC voltage between the jig 11 and anode 13 thereby forming a plating film on the substrate 12 by supplying an electric current via the plating solution Q.
A feeder section 16 is provided on the jig 11. The feeder section 16 includes a plurality of feeder contacts 15 contacting the conductive area on the surface of the substrate 12. The power source 14 is electrically connected to the feeder contacts 15 thereby a plating current flows through the anode 13, substrate 12, and feeder contacts 15.
Therefore, if the feeder contacts 15 do not reliably contact the conductive film on the substrate 12, either the plating process cannot be performed or the plating film formed on the substrate 12 will not be uniform. The conventional apparatus does not have a method or device for facilitating confirmation of the contact state between the feeder contacts 15 and the conductive film on the substrate 12.
In view of the foregoing, it is an object of the present invention to provide a plating apparatus capable of forming a plating film of uniform thickness by supplying a uniform plating current through a plurality of feeder contacts contacting the conductive area of the substrate. It is another object of the present invention to provide a conductivity sensing device for detecting the conductivity (contact state) of the plurality of feeder contacts.
To solve the above mentioned subject matter, there is provided a method for confirming conductivity state between a plating jig having a plurality of conducting pins and a substrate to be plated having a conductive film, the substrate being mounted on the plating jig having a plurality of conducting pins such that the conducting pins contact the conductive film thereon, the method comprising: disposing the conducting pins of the plating jig being electrically separated independently with each other; attaching an end of reverse-current blocking diode to wiring connecting to the conducting pins, and connecting to the other ends of the reverse-current blocking diodes together to wiring connecting to a plating power source; and measuring an electrical resistance between the wiring so as to measure the electrical resistance between conducting pins of the plating jig.
According to another aspect of the present invention, the conductivity state detector may comprise a contact resistance measuring device for measuring contact resistance between the feeder contacts and the conductive area on the surface of the substrate and detects the conductivity state of the feeder contacts based on the contact resistance measured by the contact resistance measuring device.
According to another aspect of the present invention, the conductivity state detector may comprise a current sensor for detecting current flowing through each of the plurality of feeder contacts and detects the conductivity state of the feeder contacts based on the current detected by the current sensor.
According to another aspect of the present invention, the plating apparatus may comprise a plating current detector for detecting a plating current flowing through the feeder contacts; and a plating current controller for maintaining a uniform plating current flowing through the feeder contacts based on output from the plating current detector.